Battery box for vehicle

Abstract

The invention relates to a battery case of a battery. An upper case and a lower case of the battery case are overlapped to form an internal space for accommodating a battery pack. In the lower case, the flat surface portion of the frame member is attached to the back surface of the bottom plate in a surface-contact manner, and a recess is formed in the bottom plate so as to extend from a contact region where the flat surface portion is in surface contact to a non-contact region within the cutout portion of the frame member. Thus, in the lower case, since the coating liquid enters the contact area even in a state where the frame member is attached, coating irregularities in which the coating film is thinned or the substrate is exposed can be prevented from occurring, and the development of rust or rust can be suppressed.

Description

Technical Field

[0001] This invention relates to battery boxes for vehicles. Background Technology

[0002] Japanese Patent Application Publication No. 2021-123227 describes a battery pack installed on the floor of a vehicle. Multiple battery cells are arranged in a battery pack housing, which has a lower housing and an upper housing. The battery cells are arranged side-by-side in the lower housing, and the upper housing isolates the space where the battery cells are arranged in the lower housing from the surrounding environment. Furthermore, the lower housing of the battery pack is fixed to the vehicle floor. Summary of the Invention

[0003] On the other hand, steel plates are used in the lower and upper boxes of the battery pack (battery box). Electrophoretic coating is applied to the lower and upper boxes to improve rust resistance. Regarding electrophoretic coating, for example, the lower and upper boxes to be coated are immersed in an electrophoretic coating solution using a charged cationic resin as the coating material. The object to be coated (cathode) is used as an electrode (cathode), and an electrophoretic voltage corresponding to pre-set electrophoretic conditions is applied between it and another electrode (anode) disposed in the electrophoretic coating solution. Thus, the coated objects such as the lower box suppress the occurrence of rust by forming a coating film (resin film) containing cationic resin on their surface.

[0004] However, various components for fixing to the vehicle body are installed on the battery box, and sometimes the upper and lower boxes are painted separately while these components are installed. In this case, for example, when other components are in contact with the outer surface of the lower box, the paint cannot penetrate properly at the contact surfaces, resulting in an inadequate coating and sometimes exposing the substrate. Because the substrate is exposed when the coating is not properly formed on the outer surface of the battery box, rust can occur or existing rust can worsen. Therefore, there is room for improvement in the painting process (coating formation).

[0005] The present invention was made in view of the above circumstances, and its object is to provide a vehicle battery box that can be properly painted even when the mounting component is mounted in contact with the surface of the vehicle battery box.

[0006] To achieve the above objectives, a vehicle battery box according to the first embodiment includes: a box body that houses a battery module composed of multiple stacked battery cells in an internal space; and a mounting component that is surface-contactly mounted to the outer surface of the box body and is coated together with the box body. A groove-shaped recess is formed on the outer surface of the box body, the recess extending from a contact area where the mounting component is surface-contacted to a non-contact area of ​​the mounting component.

[0007] In the vehicle battery box according to the first embodiment, a battery module composed of multiple stacked battery cells is housed within the internal space of the box body. A mounting component is installed on the box body in contact with its outer surface. Furthermore, the box body is painted while the mounting component is installed.

[0008] Here, a groove-shaped recess is formed on the outer surface of the box body, and the recess is formed from the contact area where the mounting component is in surface contact to the non-contact area of ​​the mounting component.

[0009] Therefore, on the outer surface of the box body, since the paint that enters the recess in the non-contact area reaches the contact area along the recess, the paint can properly form a coating film even in the contact area. Thus, the formation or development of rust can be inhibited on the outer surface of the box body.

[0010] According to the second embodiment of the vehicle battery box, in the first embodiment, the box body includes: a lower box, which holds the battery module; and an upper box, which covers the lower box and forms an internal space between the upper box and the lower box to accommodate the battery module, wherein the recess is formed in the lower box.

[0011] In the vehicle battery box according to the second method, the box body includes an upper box and a lower box, with a recess formed in the lower box. Therefore, even when mounting components for supporting the box body to the vehicle body are installed in the lower box, proper painting of the lower box is possible, effectively suppressing rust or rust development in the lower box.

[0012] According to the third type of vehicle battery box, in the second type, the recess is formed at the front end of the lower box in the vehicle longitudinal direction.

[0013] In the vehicle battery box according to the third method, a recess is formed at the front end of the lower box in the vehicle's longitudinal direction. This improves the rigidity of the front portion of the lower box in the vehicle's longitudinal direction, and suppresses deformation even when the lower box is subjected to load from the front side in the vehicle's longitudinal direction during an emergency.

[0014] According to the method of the present invention, the following effects can be achieved: even when the mounting component is mounted face-to-face with the outer surface of the box body, the coating can be promoted to penetrate the contact surface. Therefore, a suitable coating film can be formed on the box body without exposing the substrate, rusting on the box body can be suppressed, and even if rusting occurs, its development can be inhibited. Attached Figure Description

[0015] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention are described below with reference to the accompanying drawings, in which similar reference numerals denote similar parts, wherein:

[0016] Figure 1 This is a perspective view showing the schematic structure of the battery according to this embodiment.

[0017] Figure 2 It is a plan view showing the main part of the lower box from below.

[0018] Figure 3 It is a three-dimensional view taken from the left rear side, looking down at the main parts of the lower box.

[0019] Figure 4 It is a plan view showing the main part of the lower box according to the modified example from below. Detailed Implementation

[0020] Hereinafter, a vehicle battery box according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, the vehicle battery box is used in a vehicle.

[0021] exist Figure 1 The schematic structure of the battery 10 according to this embodiment is shown in a perspective view. Furthermore, in the figure, the front in the vehicle's longitudinal direction is indicated by arrow FR, the right in the vehicle's width direction by arrow HR, and the top by arrow UP.

[0022] Battery 10 is used, for example, in vehicles equipped with an electric motor (electric motor) as a drive source for driving (omitted in the figure), and outputs direct current suitable for driving the electric motor. Examples of vehicles equipped with battery 10 include hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), and battery electric vehicles (BEV).

[0023] like Figure 1 As shown, the battery 10 is equipped with: a battery box 12, which serves as a vehicle battery box and box body according to this embodiment; and a battery pack 14, which is housed within the battery box 12. The battery box 12 is disposed on the underside of the floor panel, which serves as the floor of the vehicle, and on the upper side of the underbody, and is mounted on the vehicle body (all figures omitted).

[0024] The battery box 12 is equipped with an upper box 20 and a lower box 22, with the upper box 20 on the upper side and the lower box 22 on the lower side facing each other. Figure 2 In the middle, a bottom-view plan (rear view) shows the main parts of the lower box 22. Figure 3 In the middle, a three-dimensional view from the left rear obliquely downwards shows the general outline of the main parts of the lower box 22.

[0025] like Figures 1 to 3 As shown, the lower box 22 is made of steel plate or the like and is equipped with a base plate 24 that is rectangular in plan view and flat on the back side. Furthermore, a peripheral wall 26 is erected around the base plate 24, and a flange portion 28 is formed on the peripheral wall 26, bending outwards from the top of the lower box 22, covering approximately the entire circumference. The base plate 24, peripheral wall 26, and flange portion 28 of the lower box 22 are integrally formed, and the lower box 22 is approximately rectangular in shape (or basin-shaped).

[0026] Furthermore, the upper box 20 is made of steel plate or the like and is equipped with a top plate 30 that is generally rectangular in plan view. Additionally, in the upper box 20, a peripheral wall 32 protrudes downwards around the top plate 30, and the front end (lower end) of the upper box 20 folds back outwards approximately around the entire circumference of the peripheral wall 32 to form a flange 34. Furthermore, the top plate 30, peripheral wall 32, and flange 34 of the upper box 20 are integrally formed.

[0027] In the battery box 12, the upper box 20 and the lower box 22 are assembled after being pre-coated for rust prevention. At this time, the flange 34 of the upper box 20 and the flange 28 of the lower box 22 overlap facing each other. In addition, in the battery box 12, the flange 34 of the upper box 20 and the flange 28 of the lower box 22 are assembled by fastening with bolts, nuts and other fastening mechanisms, and the internal space is sealed off from all sides (illustration omitted).

[0028] In addition, in the battery box 12, the junction of the top plate 30 and the peripheral wall 32 of the upper box 20, and the junction of the bottom plate 24 and the peripheral wall 26 of the lower box 22 are chamfered.

[0029] Within the battery 10, a battery pack 14, consisting of one or more battery modules 16, is housed within the internal space of the battery box 12. The battery modules 16 are arranged and configured within the battery box 12, covered from the top and bottom by a bottom plate 24 and a top plate 30, and surrounded by peripheral walls 26 and 32. Thus, the battery box 12 functions as a battery pack housing the battery pack 14.

[0030] In the battery module 16, multiple battery cells (not shown in the figure) are stacked. In the battery 10, for example, multiple battery modules 16 are connected in parallel or in series, and the battery 10 outputs direct current with the required voltage when discharging. In addition, the battery 10 charges each of the multiple battery cells in the battery module 16 by being input with the required voltage of direct current. In addition, the battery box 12 is not limited to accommodating multiple battery modules 16, and may also be in the form of accommodating a single battery module 16, or may be in the form of accommodating one or more hydrogen containers for fuel cells in addition to the battery modules 16.

[0031] On the other hand, a support frame 40 containing other components is installed in the battery box 12, and the battery box 12 is mounted to the vehicle body via the support frame 40. In this embodiment, the support frame 40 is mounted to the lower box 22, and the lower box 22 is mounted to the vehicle body 22 via the support frame 40. In addition, the support frame 40 includes a mounting member made of steel plate, and the support frame 40 can be painted together with the lower box 22 while the mounting member made of steel plate is mounted on the lower box 22.

[0032] The support frame 40 is formed by connecting multiple components to create a rectangular frame in plan view. The support frame 40 faces the periphery of the base plate 24 on the lower side of the lower box 22. In addition, the support frame 40 is mounted, for example, across the base plate 24 and the peripheral wall 26.

[0033] The support frame 40 includes a frame component 42 that contacts the lower surface of the base plate 24 of the lower box 22. The frame component 42 is a different component from the components constituting the battery box 12 and is mounted in contact with the outer surface of the battery box 12.

[0034] The lower box 22 (battery box 12) has corner portions 44 at four locations. In this embodiment, as an example, the following cases will be described: the frame member 42 is installed at the corner portion 44RF located at the front of the lower box 22 in the vehicle longitudinal direction and the right side of the lower box 22 in the vehicle width direction, and at the corner portion 44LF located at the front of the lower box 22 in the vehicle longitudinal direction and the left side of the lower box 22 in the vehicle width direction. In this embodiment, corner portion 44RF will be mainly described, and the description of corner portion 44LF will be omitted. Alternatively, the frame member 42 may also be installed at the corner portion 44RB located at the rear of the lower box 22 in the vehicle longitudinal direction and the right side of the lower box 22 in the vehicle width direction, and at the corner portion 44LB located at the rear of the lower box 22 in the vehicle longitudinal direction and the left side of the lower box 22 in the vehicle width direction.

[0035] like Figure 2 As shown, the frame member 42 has a support portion 46 facing the lower surface of the base plate 24 of the lower box 22, and a protrusion 48 that is the outer side of the base plate 24 (closer to the outer side of the lower box 22 than the base plate 24). Additionally, the frame member 42 includes a connecting portion 50 facing the outer surface of the peripheral wall 26 of the lower box 22. In the frame member 42, the connecting portion 50 connects the support portion 46 and the protrusion 48 to form a single unit.

[0036] A flat portion 52 is provided in the support portion 46 of the frame component 42, which contacts the lower surface of the base plate 24. Furthermore, in the flat portion 52, a cutout 54 is formed in the middle portion in the front-rear direction, shaped as a cut from the left to the right in the vehicle width direction. Additionally, in... Figure 2 In the middle, the outline (shape) of the planar part 52 is represented by a double-dotted line.

[0037] On the other hand, in the bottom plate 24 of the lower box 22, the area that contacts the flat surface 52 of the frame member 42 serves as the contact area 56 (in Figure 2 (The shaded area formed by the dotted line). In the base plate 24, a recess 58 is formed in the contact area 56. The recess 58 is a groove-shaped opening on the back of the base plate 24. In the contact area 56, one end is the corner 44RF side, and the other end extends to the outside of the contact area 56. The end of the recess 58 opposite to the corner 44RF side reaches into the cutout 54 of the frame member 42. Thus, the recess 58 is formed in the base plate 24 from the position corresponding to the cutout 54 of the support 46 toward the angle 44RF. The recess 58 is inclined relative to the vehicle front-rear direction and the vehicle width direction, respectively, as it moves toward the right side of the vehicle width direction towards the front of the vehicle.

[0038] In addition, such as Figure 3 As shown, in the lower box 22, a protruding rib 60 is formed on the upper surface of the base plate 24 (the side opposite to the lower surface, the side facing the internal space) by forming a recess 58. The protruding rib 60 protrudes from the upper surface of the base plate 24 and extends along the recess 58. That is, the protruding rib 60 in the upper surface of the base plate 24 is formed in the same manner as the recess 58, tending towards the left side (inner side in the vehicle width direction) from the corner 44RF side toward the rear of the vehicle.

[0039] In the base plate 24, the thickness decreases and strength is reduced by forming a recess 58 on one side (lower surface side) in the thickness direction. Here, a protruding rib 60 is formed on the other side (upper surface side) in the thickness direction of the base plate 24 to compensate for the thickness change caused by forming the recess 58. In the lower box 22, the protruding rib 60 is formed to prevent the thickness of the base plate 24 from decreasing due to the recess 58, thus preventing a decrease in strength in the thickness direction of the base plate 24.

[0040] Additionally, the recess 58 and the convex portion 60 correspond to the frame member 42 mounted on the corner 44LF and are formed near the corner 44LF of the base plate 24 (omitted in the figure). At this time, the recess 58 and the convex portion 60 are formed in such a way that they tend to move inward in the vehicle width direction (to the right in the vehicle width direction) from the corner 44LF side toward the rear of the vehicle.

[0041] Next, the function of this implementation method will be explained.

[0042] The battery 10 is provided with a battery box 12, on which a battery module 16 composed of multiple stacked battery cells is disposed (fixed) on the lower box 22 and covered by the upper box 20. Thus, the battery 10 houses the battery module 16 (battery pack 14) within the battery box 12.

[0043] Furthermore, in the battery 10, a support frame 40 is installed on the lower box 22 of the battery box 12. The lower box 22 is mounted to the vehicle body via the support frame 40, and the battery box 12 is supported on the vehicle body. Thus, the battery 10 is mounted in the vehicle.

[0044] On the other hand, in vehicles, electrophoretic coating is mostly used for the formation of coatings on various components. For example, cationic electrophoretic coating solutions are used, employing epoxy resin as a matrix and cationic resin as the coating material. In cationic electrophoretic coating, the upper container 20 or lower container 22, which is the object to be coated, is immersed in a cationic coating solution containing a positively charged cationic resin. Furthermore, in electrophoretic coating, the upper container 20 or lower container 22 is used as one electrode (cathode) in a pair of electrodes (anode and cathode), and an electrophoretic voltage corresponding to pre-set electrophoretic conditions is applied between it and the other electrode (positive electrode) disposed in the coating solution. As a result, the coating material (coating component) from the coating solution is deposited on the surface of the upper container 20 or lower container 22, and the object to be coated is covered by a coating film (resin coating film) (forming a coating film).

[0045] In this electrophoretic coating process, the mounting component 42 can be coated along with the lower box 22, as the mounting component 42 is coated. However, the flat portion 52 of the mounting component 42 is in surface contact, which can easily lead to uneven coating, such as thinning of the coating film or exposure of the substrate, in the contact area 56 of the lower box 22.

[0046] Here, on the base plate 24 of the lower box 22, a recess 58 is formed in the contact area 56 that contacts the flat surface 52 of the mounting component 42. The recess 58 extends from the contact area 56 to a position corresponding to the cutout 54 of the frame component 42, which becomes a non-contact area. The non-contact area of ​​the lower box 22 is open, becoming an area where the coating liquid adheres.

[0047] Therefore, on the base plate 24 of the lower box 22, the coating liquid can enter the recess 58 opened by the cutout 54, and the coating liquid is supplied to the contact area 56. That is, the recess 58 extending from the non-contact area into the contact area 56 forms a non-contact area within the contact area 56. Therefore, the situation where a region detached from the non-contact area is formed in the contact area 56 due to the recess 58 on the base plate 24 on which the frame member 42 is mounted is suppressed.

[0048] Therefore, coating liquid can be supplied to the contact area 56 of the frame member 42 on the bottom plate 24 of the lower box 22, and a coating film is formed in the contact area 56 using the coating liquid. In addition, a coating film is also formed on the bottom plate 24 side of the flat portion 52 of the frame member 42 that contacts the bottom plate 24.

[0049] In this way, even if the frame component 42 is mounted in surface contact within the lower casing 22, a suitable coating can be formed to prevent the substrate from being exposed. Consequently, rust or the development of rust spots is reliably suppressed in both the lower casing 22 and the battery box 12 on which the lower casing 22 is formed.

[0050] On the other hand, if the vehicle body is impacted during an emergency, the battery box 12 will be subjected to a load corresponding to that impact. In this case, a recess 58 with a downward opening is formed on the lower surface of the bottom plate 24 of the lower box 22, and a protruding rib 60 is formed on the internal space side of the battery box 12. Therefore, the rigidity of the bottom plate 24 of the lower box 22 is increased in the battery box 12, and deformation under external force is suppressed.

[0051] Furthermore, the protruding portion 60 is inclined near the corners 44RF and 44LF of the lower box 22 relative to the vehicle's longitudinal direction and width direction, respectively. Therefore, by using the lower box 22, the rigidity of the battery box 12 is improved relative to the loads in both the vehicle's longitudinal and width directions. Consequently, even if the battery box 12 is subjected to loads on the front side in the vehicle's longitudinal direction or on both sides in the vehicle's width direction during an emergency, deformation is suppressed, thus protecting the battery pack 14 housed inside.

[0052] Furthermore, in the battery box 12, recesses 58 and raised stripes 60 are provided at the corners 44RF and 44LF of the lower box 22. However, the recesses 58 and raised stripes 60 may also be formed at the rear corners 44RB and 44LB of the lower box 22 in the vehicle longitudinal direction. Thus, in the battery box 12, the rigidity relative to the loads received from the rear side in the vehicle longitudinal direction and from both sides in the vehicle width direction of the rear of the vehicle can be improved, and the battery pack 14 can be protected relative to the loads received from the rear side in the vehicle longitudinal direction and from both sides in the vehicle width direction of the rear of the vehicle.

[0053] In this embodiment, a recess 58 is formed in the lower housing 22 in the contact area 56 with the frame member 42, reaching the cutout 54 in the frame member 42. However, the recess 58 can be formed in such a way that it extends from the contact area 56 with the frame member 42 to a non-contact area that does not contact the frame member 42.

[0054] exist Figure 4 In the diagram, the main part of the lower box 22 according to the modified example is shown in a plan view (rear view) from below.

[0055] In a modified example, the frame member 42 has a circular hole 62 in the support portion 46 on the rear side of the planar portion 52 in the vehicle longitudinal direction, and the circular hole 62 is formed through the support portion 46 in the vertical direction. As a result, the lower surface of the lower box 22 opens downward by means of the circular hole 62.

[0056] For this frame component 42, a recess 64 can also be formed on the bottom plate 24 of the lower box 22, extending from the contact area 56 to a position opposite to the circular hole 62 of the support portion 46. Thus, the coating liquid entering the circular hole 62 of the support portion 46 enters the recess 64, thereby allowing the coating liquid in the contact area 56 of the bottom plate 24 of the lower box 22 to penetrate from the recess 64 and adhere between the bottom plate 24 and the flat portion 52.

[0057] Therefore, even when a recess 64 is formed in the base plate 24 instead of a recess 58, the same as when a recess 58 is formed, it can prevent the coating from becoming thin or the base of the base plate 24 from becoming uneven, and can suppress the development of rust or rust spots in the lower box 22.

[0058] Furthermore, in this embodiment and its variations, recesses 58 and 64 are formed in the bottom plate 24 of the lower box 22. However, recesses may also be provided in the top plate 30 of the upper box 20 relative to the mounting members installed near the corner 44. In this case, it is preferable to form a raised portion corresponding to the recess. This can prevent uneven coating on the top plate 30 of the upper box 20 and suppress the generation or development of rust. Moreover, the rigidity of the upper box 20 and the battery box 12 can be improved by means of the raised portion formed together with the recess.

[0059] Furthermore, the recess is not limited to being formed at the corner; it can also be formed near the straight section between the corners. That is, the recess can also be formed relative to a mounting member mounted on the outer surface of the peripheral wall 32 of the upper box 20 or the outer surface of the peripheral wall 26 of the lower box 22. As a result, uneven coating can be prevented in the peripheral wall 32 of the upper box 20 and the peripheral wall 26 of the lower box 22, and the rigidity of the peripheral walls 26 and 32 can be improved by means of the raised portion formed corresponding to the recess.

Claims

1. A battery case for a vehicle, wherein, Comprising: a case body that houses a battery module in which a plurality of battery cells are stacked inside a space; and a mounting member that is mounted in surface contact with an outer surface of the case body, and is painted together with the case body, a groove-shaped recessed portion is formed in the outer surface of the case body, and reaches from a contact area that is in surface contact due to the mounting of the mounting member to a non-contact area of the mounting member.

2. The battery box for a vehicle according to claim 1, wherein The case body includes: a lower case that places the battery module; and an upper case that covers the lower case, and forms an inner space that houses the battery module between the lower case, the recessed portion is formed in the lower case.

3. The battery box for a vehicle according to claim 2, wherein The recessed portion is formed in a front side end portion in a vehicle front-rear direction of the lower case.

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